Solid oxide fuel cell anodes ceramic

Corbin SF and Qiao X. Development of solid oxide fuel cell anodes using metal-coated pore-forming agents. J Am Ceram Soc 2003 86 401-406. 

Offer G J, Mermelstein J, Brightman E and Brandon N P, Thermodynamics and kinetics of the interaction of carbon and sulfur with solid oxide fuel cell anodes. Journal of the American Ceramic Society, 2009, 92, 763-780. 

Madsen B, Barnett S (2005) Effect of fuel composition on the performance of ceramic-based solid oxide fuel cell anodes. Solid State Ion 176 2545-2553... 

Primdahl S, Sprensen BF, and Mogensen M. Effect of nickel oxide/yttria-stabilized zirconia anode precursos sintering temperature on the properties of solid oxide fuel cells. J Am Ceram Soc 2000 83 489 -94. 

Sarkar P, Yamarte L, Rho H, and Johanson L. Anode-supported tubular micro-solid oxide fuel cell. Int. J. Appl. Ceram. Technol. 2007 4 103-108. 

A solid oxide fuel cell (SOFC) consists of two electrodes anode and cathode, with a ceramic electrolyte between that transfers oxygen ions. A SOFC typically operates at a temperature between 700 and 1000 °C. at which temperature the ceramic electrolyte begins to exhibit sufficient ionic conductivity. This high operating temperature also accelerates electrochemical reactions therefore, a SOFC does not require precious metal catalysts to promote the reactions. More abundant materials such as nickel have sufficient catalytic activity to be used as SOFC electrodes. In addition, the SOFC is more fuel-flexible than other types of fuel cells, and reforming of hydrocarbon fuels can be performed inside the cell. This allows use of conventional hydrocarbon fuels in a SOFC without an external reformer. 

Fig. 11. Assemblers Dionne Davis and John Sige clean excess nickel anode materia] from ceramic lubes which arc the heart of ihe Wesiinghouse solid-oxide fuel cell. [Westinghoii.se Eiecxrk Corporation)...

The working principles behind a solid oxide fuel cell (SOFC) are schematically illustrated in Figure 8.7, where, similar to the other fuel cell types, the three key parts of an SOFC, a cathode, an anode, and an electrolyte, are shown. The electrolyte is, in a majority of cases, an oxygen-anion ceramic conductor, which is, as well, an electronic insulator [5]. In the SOFC the fuel can be methane (CH4). Subsequently, in this case the oxidation reaction in the anode is given by... 

Solid oxide fuel cells (SOFC), which use oxygen conducting ceramic membranes to electo-combust H2, at the anode, by 02 -anions provided by the cathodic reduction of ambient oxygen at high temperatures. 

PEVD has been applied to deposit auxiliary phases (Na COj, NaNOj and Na SO ) for solid potenfiometric gaseous oxide (CO, NO, and SO ) sensors, as well as a yttria stabilized zirconia (YSZ) ceramic phase to form composite anodes for solid oxide fuel cells. In both cases, the theoretically ideal interfacial microstructures were realized. The performances of these solid state ionic devices improved significantly. Eurthermore, in order to set the foundation for future PEVD applications, a well-defined PEVD system has been studied both thermodynamically and kinetically, indicating that PEVD shows promise for a wide range of technological applications. 

N. Q. Minh, J. Am. Ceram. Soc., 76, 563 (1993). Excellent review of the solid oxide fuel cell including a thorough treatment of the ceramic components (electrolyte, anode, cathode, and interconnect). 

R.M.C. Marques, J.R. Frade and F.M.B. Marques, Ceramic materials for SOFC anode cermets, in S.C. Singhal and H. Iwahara (Eds.), Proceedings of the 3rd International Symposium on Solid Oxide Fuel Cells. The Electrochemical Society, Pennington, NJ, 1989, pp. 513-522. 

Solid oxide fuel cell (SOFC) uses solid ceramic material, such as Y2O3 stabilized Zr02 (YSZ), as an electrolyte. As SOFC operates at high temperature (600-1000° C), a variety of fuels, e.g., hydrogen, methane, and carbon monoxide, can directly be utilized. The high temperature places severe constraints on material selection and results in difficult fabrication process. Co-ZrO (or Ni-ZrO) and SrO doped LaMn03 have often been used for anode and cathode materials, respectively. 

The main component of a solid oxide fuel cell is a three-layered sandwich consisting of anode, electrolyte, and cathode, each being made from a different oxide ceramic material. Such ceramic structures can be fabricated by various methods including slip or tape casting, injection molding, ceramic coverings, etc. [1]. Whatever the method applied is, it should provide the best able microstructure and specified performance of materials besides the desired shape of a SOFC membrane. However, layers of the membrane have different properties that requires combination of two or more different methods of ceramic engineering in the component fabrication. 

The anodes consisting of a nickel catalyst and of cermet mixed with yttria-doped zirconia electrolyte that are used in conventional solid oxide fuel cells also lose their ability to work at lower temperatures because of a loss of conductivity by the ceramic. This suggests that, for the ceramic in the anode, a material having a higher conductivity at intermediate temperatures should be used. It was in fact shown that an anode made with a nickel/samaria-doped ceria cermet has a much lower polarization than the conventional variant. 

R. N. Basu, G. Blass, H. P. Buchkremer, D. Stver, F. Tietz, E. Wessel, and I. C. Vinke. SimpUlied processing of anode-supported thin film planar solid oxide fuel cells. J. European Ceramic. Soc. 25, (2005) 463 71. 

The prevalent material for substrates and anodes in anode-supported solid oxide fuel cells (SOFCs) are porous composites of oxygen-ion conducting ceramics such as yttria-stabilised zirconia (YSZ) and Nickel. Cells based on such substrates and anodes have been found to show very good performance. ... 

W.A. Meulenberg, N.H. Menzler, H.-P. Buchkremer and D. Stover, Manufacturing Routes and State-of-the-art of the Planar Juelich Anode-Supported Concept for Solid Oxide Fuel Cells, Ceramic Transactions, 127, p. 99 (2002)... 

J. Malzbender, E. Wessel, R.W. Steinbrech and L. Singheiser, Reduction and re-oxidation of anodes for solid oxide fuel cells, Proc. 28" International Conference on Advanced Ceramics and Composites A, (Eds. E. Lara-Curzio, M.J. Readey), Cocoa Beach, USA, p. 387 (2005)... 

Metal Supported-Solid Oxide Fuel Cells (MS-SOFC) represent a promising new design for fuel cells which may overcome the limitations of anode-supported cells (such as poor thermal cycling resistance and brittleness. Nickel phase re-oxidation upon exposure to transient uncontrolled conditions) due to the much better mechanical properties of the support that is represented by a porous thick metal substrate, the thickness of the ceramic layers (anode/electrolyte/cathode) being in the order of 10-50 pm, only. In addition, in this design (Fig. 1), the replacement of the thick Ni/YSZ cermet with ferritic stainless steel leads to several benefits in term of fabrication cost and safety. 

---